Aromatic amino acid hydroxylases



The enzyme family of aromatic amino acid hydroxylases consists of phenylalanine hydroxylase (PAH), tyrosine hydroxylase (TH) and tryptophan hydroxylase (TPH).

These enzymes all contain iron and use BH4 as a co-substrate in the hydroxylation of their respective aromatic amino acids. Additionally all mammalian AAAH form homotetramers and each monomer consists of three domains. These domains are the N-terminal regulatory domain (100-150 residues), the catalytic domain (approximately 315 residues) and the C-terminal tetramerisation domain (approximately 30-40 residues).

3D structures of Aromatic amino acid hydroxylases
Phenylalanine hydroxylase

Tyrosine hydroxylase

Tryptophan hydroxylase

Additional Resources
For additional information, see: Amino Acid Synthesis & Metabolism